Inconclusive Pap Smear?

From the WebMD Archives

Jan. 16, 2002 -- Most women know that having an annual Pap smear is the best way to catch cervical cancer while it is still highly treatable, but what should you do when the results come back inconclusive? Roughly 2 million women and their doctors face that question each year, and the answer is far from simple.

While some doctors take a watch-and-wait approach to inconclusive Pap tests, others recommend an expensive, and sometimes painful, diagnostic procedure known as a colposcopy. Now, new research from the National Cancer Institute (NCI) confirms that performing a simple viral test is a useful third approach.

Last year, NCI researchers reported that testing women with inconclusive smears for the human papillomavirus (HPV) -- the sexually-transmitted virus that causes genital warts -- could help identify those who did not have cervical cancer or precancerous cells. That study found that a negative HPV test indicated with 99% certainty that a woman did not have cervical cancer. New research, reported in the Jan. 16 issue of the Journal of the National Cancer Institute, suggests that the test is highly sensitive for all women, no matter what their age.

Human papillomavirus is now recognized as the cause of essentially all cervical cancers, so a negative HPV test is proof that a woman does not have the disease. With this in mind, one of the nation's largest women's health organizations now recommends that all women with inconclusive Pap smears receive HPV testing.

"We don't want to interfere with anyone's relationship with their doctor, but we know that there are still many physicians out there who are not routinely offering HPV testing to these patients," says gynecologist Angel Houghton, MD, who chairs the American Medical Women's Association's national HPV and cervical cancer campaign.

"We want women to know that this is an option. What I have seen in my community is that women are simply told to repeat their Pap smear every four to six months until they have three that are normal. That means it takes a year to a year-and-a-half to know that everything is OK. For many women that is emotionally unacceptable."


Everything does turn out to be OK for the vast majority of women who have abnormal or inconclusive Pap smears. Of the more than 2 million Pap smears that are labeled suspicious each year, only about 5-10% turn out to be cancerous or precancerous. Approximately 13,000 women in the U.S. are diagnosed with cervical cancer annually, and 4,400 die from it.

Although a negative HPV test can be considered conclusive, a positive test means little because roughly 40 million Americans have the virus. HPV is one of the most common sexually transmitted diseases in the U.S., and more than 60 types of the virus have been identified. Only a handful, however, are associated with cervical cancer.

The NCI researchers evaluated the value of HPV testing in nearly 2,200women with inconclusive Pap results identified as atypical squamous cells of undetermined significance (ASCUS) and another 848 women with low-grade squamous intraepithelial lesions (LSIL). Among women with LSIL, testing for HPV was not useful in identifying those who didn't need colposcopies. But among those with ASCUS, it was.

"We found that the test was equally sensitive for all ages, but the predictive value of the test -- the number of positive women who actually have the disease -- was much higher in older women," lead author Mark E. Sherman, MD, of NCI's Environmental Epidemiology Branch, tells WebMD.

"As people get older, their background infection level actually goes down," he says. "So when we do see the infection it may mean more. We know that most women who test positive for HPV do not have cervical cancer, but that may be especially true for younger women."

The American Medical Women's Association is the first major health organization to weigh in on the subject of HPV testing in cervical cancer screening, but it will not be the last. Long-awaited guidelines from leading medical organizations are due to be made public within the next few months.